[unreadable] Intrauterine nutrition appears to affect risk for chronic disease, including obesity and diabetes, in adulthood (the fetal programming hypothesis). For this reason, research into the effects of maternal diet on offspring outcomes is of potentially great public health significance. Of particular relevance to this proposal, women with impaired glucose tolerance are more likely to have large babies, and postprandial glycemic excursions in non-diabetic pregnancy directly predict birth weight. High birth weight, in turn, is directly associated with adult BMI. However, there are presently no specific dietary recommendations for pregnancy complicated by impaired glucose tolerance but not diabetes. In this pilot study, we aim to examine the hypothesis that women who consume a low glycemic load diet (ie, one designed to decrease postprandial glycemia) in the third trimester will give birth to babies who weigh less than women who consume a conventional diet. We propose a randomized controlled feeding study. Participants, 60 woman age 25 years or older with impaired glucose tolerance, will be recruited from the outpatient clinics at Beth Israel Deaconess Medical Center, Boston. After confirming eligibility by an oral glucose tolerance test, subjects will be assigned to either a low glycemic load diet or a conventional diet designed to satisfy all current nutritional recommendations for optimal health during pregnancy. At gestational week 28, participants will begin the feeding protocol, in which all carbohydrate rich foods and snacks will be prepared in the metabolic kitchen at the Children's Hospital. The primary endpoint will be birth weight of the offspring; the process/compliance measure will be unannouced 24h dietary recall; secondary endpoints will include maternal weight gain, metabolic syndrome components in the mother, and adiposity and cord blood analysis in the infant. A successful outcome of this study will provide preliminary data upon which to design a multi- centered clinical trial. [unreadable] [unreadable] [unreadable]